Understanding Photoinduced Memory Effects in Optoelectronic Devices across Photoresponse Time Scales for Sensor-Based Artificial Intelligence

As recent optoelectronic devices evolve beyond passive light sensors, their photoinduced memory effects are offering new possibilities for sensor-based artificial intelligence through the integration of sensing and computation. These applications have been developed utilizing a broad range of photoresponse times; however, a comprehensive, unified perspective for categorizing these mechanisms based on response time remains elusive. By encompassing the fast-decaying responses in photodetectors and the persistent memory states in optoelectronic synapses, this perspective provides a systematic framework for understanding the broad spectrum of photoresponse time scales associated with photoinduced memory effects in optoelectronic devices. We first introduce the mechanisms of photocurrent generation through photoconductive and photogating effects, and then we provide an overview of photoresponse times, both with and without consideration of recombination time, covering volatile and nonvolatile processes. Finally, we highlight the role of photoinduced memory effects in various emerging intelligent sensor technologies.